Use preg_replace to replace the contents of a tag

I often need to replace the contents of a tag using php with another variable. This is made easy with the preg_replace() function and a nifty regular expression.

$content = '
Some content to replace
';
echo $content;
//output: 
 Some content to replace

//replace content using preg_replace and regex:
$content = preg_replace('/]*>.*?<\/div>/i', '
New Content', $content);

echo $content;

// new output: 
// 
New Content

http://stackoverflow.com/questions/7139342/preg-replace-how-to-remove-contents-inside-a-tag